Effects of soil colloids on adsorption and migration of benzo(a)pyrene on contaminated sites under runoff infiltration processes

Jianlong Wang; Zhimeng Han; Changhe Zhang; Meiqi Wang; Hongxin Li; Dawen Gao

doi:10.1016/j.envpol.2024.124150

Effects of soil colloids on adsorption and migration of benzo(a)pyrene on contaminated sites under runoff infiltration processes

Environ Pollut. 2024 May 10:353:124150. doi: 10.1016/j.envpol.2024.124150. Online ahead of print.

Authors

Jianlong Wang¹, Zhimeng Han², Changhe Zhang³, Meiqi Wang², Hongxin Li², Dawen Gao⁴

Affiliations

¹ Key Laboratory of Urban Stormwater System and Water Environment, Ministry of Education, Beijing University of Civil Engineering and Architecture, Beijing, 100044, China; Beijing Energy Conservation & Sustainable Urban and Rural Development Provincial and Ministry Co-construction Collaboration Innovation Center, Beijing, 100044, China. Electronic address: wangjianlong@bucea.edu.cn.
² Key Laboratory of Urban Stormwater System and Water Environment, Ministry of Education, Beijing University of Civil Engineering and Architecture, Beijing, 100044, China; Beijing Energy Conservation & Sustainable Urban and Rural Development Provincial and Ministry Co-construction Collaboration Innovation Center, Beijing, 100044, China.
³ Key Laboratory of Urban Stormwater System and Water Environment, Ministry of Education, Beijing University of Civil Engineering and Architecture, Beijing, 100044, China; China Academy of Building Research, Beijing, 100013, China.
⁴ Key Laboratory of Urban Stormwater System and Water Environment, Ministry of Education, Beijing University of Civil Engineering and Architecture, Beijing, 100044, China.

PMID: 38735466
DOI: 10.1016/j.envpol.2024.124150

Abstract

In the environment, soil colloids are widespread and possess a significant adsorption capacity. This makes them capable of transporting different pollutants, presenting a potential risk to human and ecological well-being. This study aimed to examine the adsorption and co-migration characteristics of benzo(a)pyrene (BaP) and soil colloids in areas contaminated with organic substances, utilizing both static and dynamic batch experiments. In the static adsorption experiments, it was observed that the adsorption of BaP onto soil colloids followed the pseudo-second-order kinetic model (R² = 0.966), and the adsorption isotherm conformed to the Langmuir model (R² = 0.995). The BaP and soil colloids primarily formed bonds through π-π interactions and hydrogen bonds. The dynamic experimental outcomes revealed that elevating colloids concentration contributed to increased BaP mobility. Specifically, when the concentration of soil colloids in influent was 500 mg L^-1, the mobility of BaP was 23.2 % compared to that without colloids of 13.4 %. Meanwhile, the lowering influent pH value contributed to increased BaP mobility. Specifically, when the influent pH value was 4.0, the mobility of BaP was 30.1 %. The BaP's mobility gradually declined as the initial concentration of BaP in polluted soil increased. Specifically, when the initial concentration of BaP in polluted soil was 5.27 mg kg^-1, the mobility of BaP was 39.1 %. This study provides a support for controlling BaP pollution in soil and groundwater.

Keywords: Infiltration; Langmuir model; Polycyclic aromatic hydrocarbons; Pseudo-second order kinetic model; pH value.